This invention relates to apparatus for packing a pack or lot of boards. This invention also relates to a method of packing a pack of boards. This invention also relates to a board storage unit for use in the apparatus.
This invention relates particularly but not exclusively to apparatus for handling packs or lots of boards for use in building construction, eg plasterboard and fibre-cement boards. It will be convenient to hereinafter describe this invention with reference to the example application of packs of these boards. However it is to be clearly understood that it is capable of other applications, and in particular it is suitable for handling and packing other types of boards.
In the specification the term plasterboards shall be interpreted broadly. For example plasterboards shall be interpreted to include boards made of fibre-cement and also other boards used in building construction.
Sheets of board and in particular plasterboard are used widely in building construction, particularly residential buildings and commercial buildings. For example plasterboard is used to line the internal walls and ceilings of buildings providing the interior surface finish. Other boards, eg fibre-cement boards may be used for specific rooms, eg the bathroom or kitchen, but plasterboard is used for most of the walls.
During construction the boards are supplied on site in the form of packs or lots of boards which are supplied as a single pack to the construction site. Each pack will comprise 50 to 100 boards each with a specific material, size and thickness specification. Individual houselots with their specific requirements for boards of a certain dimension and thickness are assembled or made up at a factory or distribution point and then delivered to the site in a single delivery.
Currently a large amount of manual handling is required to assemble houselots of boards at a distribution point. Individual boards would typically be lifted by a pair of packers, eg persons, who select a predetermined board type and size from a supply of boards and then stack the boards in a manner that facilitates presentation of the load to a forklift truck for loading onto a transport vehicle. There are compelling reasons to reduce the amount of manual handling of boards in the process of assembling a houselot. The weight of individual boards can exceed limits laid down by Workplace Health and Safety Regulations in at least some areas. The lifting of these boards by workers is therefore undesirable. Further the manual handling of the boards leads to high levels of pedestrian traffic on the floor which increases the potential for collision between these pedestrians and forklifts, which is a major source of industrial accidents in these environments.
In addition the process of assembling a pack of boards in this fashion is very labour intensive and it would be advantageous if the labour cost of this assembling process could be reduced making it more efficient.
It would also be advantageous if the boards in a given houselot could be sequenced or ordered in a specific order to ease the amount of handling required at the construction site. That is it would be advantageous to receive the boards in the order in which they would be used by a plasterer on site. This aspect in addition would lead to further productivity increases and cost savings in terms of the labour cost of building a house.
Accordingly it would be advantageous if apparatus could be provided for taking boards out of bins storing the boards, moving them to a packing point where they are stacked into a neat pack and then strapping them together to form a single pack which can be presented to a forklift truck for lifting onto a transport vehicle. It would also be advantageous if the process was automated and had a processing means for calculating the sequence in which boards were drawn from the bins.
According to one aspect of this invention there is provided apparatus for packing boards, the apparatus including:
a plurality of board storage units each storing a plurality of a specific size and specification of board, each board storage unit having means for dispensing a board in the board storage unit; and
a conveyor for conveying the boards in sequence from the various board storage units to a packing point such that a lot or pack of boards can be formed at the packing point comprising boards of desired sizes arranged in a desired sequence.
Thus in its broadest form the invention comprises selecting sheets of different sizes in sequence from the various board storage units and transferring them to a packing point such that the pack or batch ultimately formed at the packing point comprises boards of desired sizes arranged in a desired sequence.
The apparatus may also include selector means for determining the sequence in which boards are drawn from the board storage units and controlling dispensing of the boards from the storage units by activating the appropriate board storage units in turn to dispense the boards.
The selector means may also include a processing means that is a computer programmed with appropriate software for determining the sequence of boards in the pack or lot based on information entered into the computer.
Thus the apparatus also determines the sequence in which boards are drawn from the board storage units based on information which is entered into the processing means, eg by a customer.
This enables the boards arriving at the packing point to be ordered in a particular sequence, eg an order which is favourable to the user which typically would be a plasterer on a building site. It may also take into account the shape of the pack of boards for loading on to a truck.
Applicant has determined that 95% of boards for the typical houselot can be supplied from 40 board storage units, eg bins, each having a different sized board therein. Typically the boards have a length in the range of 2.4 meters to 5-6 meters, and a width of 1.2 meters to 1.35 meters.
Thus the pack is made up by drawing different sized boards in a desired sequence from the respective bins and transferring these in turn on the conveyor means to the packing point.
The apparatus may have at least 20 said board storage units, preferably at least 30 said board storage units, more preferably 38 to 42 board storage units and the board storage units may be sized to accommodate boards having a length of 2.4 meters to 5-6 meters and a width of 1.2 meters to 1.35 meters.
Each board storage unit or bin may be pivotable between a passive position in which the boards are horizontally extending and an active discharge position in which the boards are substantially vertically extending, and a leading board can be tipped or pushed on to the conveyor.
Typically the boards are loaded into each bin for subsequent use in forming a pack when the storage unit is in the passive position and after the loading is completed the unit is moved to the vertically extending operative position.
Each board storage unit may include advancing means for advancing the boards in the unit to a position where the board in the leading position can be tipped on to the conveyor, and lifting means for lifting the board occupying the leading position upwardly such that an upper edge thereof projects upwardly proud of the remainder of the boards in the unit.
The lifting means may comprise a resilient biasing means for lifting the leading board upwardly proud of the remainder of the boards in the unit.
The resilient biasing means may be a spring and the biasing force may be exerted more or less constantly on the board once the board is advanced to the leading position by the advancing means.
Each board storage unit may include dispensing means for detaching the leading board in the unit from the remainder of the boards and tipping the leading board onto the conveyor means. The dispensing means may include detaching means for detaching the raised leading board from the remainder of the boards and also tipping means for tipping the leading board onto the conveyor means.
In turn the detaching means may conveniently include a mechanical pusher for pushing the upper edge of the leading board in a direction away from the other boards and towards the conveying means. The tipping means may include a pneumatic blaster for issuing a blast of air at the upper edge of the leading board once it has been detached from the remainder of the boards to tip it onto the conveyor.
In one form the plurality of board storage units comprises two sets of storage units each of which comprises two rows of units with the conveyor means extending between the rows of units. Further the bins of each set may be located on two levels.
The conveyor may comprise a storage unit conveyor portion conveying the boards from the storage units to associated storage unit end points, a second conveyor portion conveying the boards laterally inwardly from said bin end points to a single transfer point, and a third conveyor portion conveying the boards longitudinally from the transfer point to the packing point.
Conveniently the storage unit conveyor portion may include belts that are suited to grip and hold boards thereon when the boards are tipped onto the belts. Belts are preferred because of their ability to grip and carry the boards. The second conveyor portion comprises one or more laterally extending conveyor sections that comprise a plurality of spaced narrow belts for moving the boards laterally from the storage unit end points to the single transfer point. The third conveyor portion comprises transverse rollers rotating in a direction towards the packing point which transfer the boards from the transfer point to the packing point, and the third conveyor portion also aligns the boards before they arrive at the packing point.
The apparatus may further include means for stacking the boards making up the pack or lot in a single stack with the boards broadly horizontally extending and substantially aligned with each other and with the boards stacked in the order in which they are drawn from the board storage units.
The stacking means may include a support for supporting the boards forming the stack and also a vacuum conveyor mounted on the support spaced above the stack for attaching the boards arriving at the packing point thereto by means of a suction attachment and drawing the boards across the stacking means into a stacking position where the board is superimposed over the stack, eg laterally and longitudinally aligned with the stack. Typically the vacuum stacking conveyor releases the board attached thereto when the board is in the stacking position by interrupting the vacuum applied to the vacuum conveyor.
The vacuum stacking conveyor may comprise an endless conveyor with suction cups projecting outwardly therefrom at intervals across the surface of the conveyor, the suction cups applying a suction attachment to the boards when they come into contact therewith.
Typically lengths of cornice are added to the pack, eg at the stacking means to complete the customer order.
The apparatus may further include a pack transfer conveyor for conveying the pack of boards formed by the stacking means to a discharge point, eg where the pack is finally lifted by a forklift truck onto a truck for transport to site.
The pack transfer conveyor may conveniently be in the form of a roller conveyor comprising a plurality of closely spaced rollers extending transversely to the direction of travel of the pack and rotating in the direction of the travel of the pack to advance the pack from the stacking means to the discharge point. The pack transfer conveyor is required to carry a load of several tonnes which is substantially heavier than the individual boards carried by the first conveyor.
The apparatus will typically also include means for attaching the pack of boards to each other to form a single article suitable for transport to a site where it is to be used. The attaching means usually comprises a strapping applicator positioned adjacent and downstream from the stacking means.
The attachment means typically also includes means for applying a cover sheet to the pack to fully enclose or encase the pack to seal it off from the ingress of moisture downstream of the strapping applicator. It is particularly important that the plasterboard does not get exposed to moisture when being transported from the distribution point to the houselot.
The apparatus may also include means for enclosing the pack in shrink-wrap to supplement the cover sheet and means for presenting the load conveniently for pick up by a fork lift truck at the discharge point.
According to a second aspect of this invention there is provided a method for assembling and wrapping a pack of boards so as to produce a single wrapped pack that can be transported to a building site, the method including:
selecting individual boards having specific dimensions in turn from one of a plurality of board storage units, each unit holding a specific size of board;
dispensing the selected boards from the board storage unit onto a conveyor as they are selected; and
conveying the boards on the conveyor in the sequence in which they are selected and dispensed to a packing point where they can be stacked to form a pack of boards.
The method may conveniently also include the step of calculating a preferred order in which boards of different sizes are selected and then dispensed from the board storage units.
Advantageously the method includes the further step of taking the boards off the conveyor as they are delivered to the packing point and depositing them onto a stack forming the pack of boards. The boards may be taken off the conveyor by means of stacking means including a vacuum conveyor.
The method may also include strapping the boards together to form a single pack after they have been formed into a stack. The method may also include the step of covering the pack with a cover sheet and also with a shrink wrap.
The method may also include the final step of transferring the strapped pack with a cover sheet and shrink-wrap to a transfer point where it can be picked up and deposited in a truck.
According to a third aspect of the invention there is provided a board storage unit for receiving a plurality of boards of a single size, the unit including:
a base;
a support for boards loaded into the storage unit, the support being mounted on the base;
means for pivoting the support between a passive position in which the boards are horizontally extending and an active discharge position in which the boards are vertically extending;
lifting means for lifting a leading board from those stored in the unit upwardly proud of the remainder of the boards when the unit is in the active discharge position; and
dispensing means for dispensing the leading board from the support and onto a conveyer.
Each unit is generally positioned in the active discharge position during normal operation of the unit but is moved to the passive position for loading of boards into the storage unit and after loading is moved back to the active discharge position.
Typically the pivoting means might comprise a hydraulic drive with a plurality of hydraulic rams.
The support member may include a first portion positioned under and supporting the boards in the passive position, and a second portion extending substantially perpendicularly to the first portion which is positioned underneath the boards in the active position and supports the boards.
The lifting means may comprise a resilient biasing means biasing the leading board upwardly proud of the remainder of the boards in the unit.
The resilient biasing means in one embodiment is a spring positioned under the board in the leading position, which applies a more or less constant force on the board in the leading position.
The dispensing means may include detaching means for detaching the raised leading board from the remainder of the boards and also tipping means for tipping the leading board onto the conveyor means.
The detaching means may include a mechanical pusher for pushing the upper edge of the leading board in a direction away from the other boards and towards the conveyor.
The tipping means may include a pneumatic blaster for issuing a blast of air at the leading board once it has been detached from the remainder of the boards to tip it onto the conveyor.
The unit may further include an overhead support member moveable relative to the bin towards and away from the conveyor, and the mechanical pusher and the pneumatic blaster may be mounted on the support member in closely spaced relation to each other.
Thus the board storage unit provides storage for boards of a particular size and also the ability to separate off a leading board and tip it on to a conveyor on demand when it is required. The unit can easily be loaded with an inventory of boards by simply dumping them on the support member when it is in the passive position with the boards in a horizontally extending orientation.
The board storage unit may include any one or more of the features relating to this unit described above with respect to the first aspect of the invention.
According to a fourth aspect of this invention there is provided a stacking means for stacking boards arriving at a packing point into a single stack making up the pack with the boards horizontally extending and substantially in line with each other.
Typically the boards are stacked in the order in which they arrive at the packing point.
The stacking means may include a support for supporting the boards forming the stack and also a vacuum conveyor mounted on the supports spaced above the stack for attaching the boards arriving at the packing point thereto by means of a suction attachment and drawing the boards across the stacking means into a stacking position where the board is superimposed over the stack, eg laterally and longitudinally aligned with the stack.
The vacuum stacking conveyor may comprise an endless belt with suction cups projecting outwardly therefrom at intervals across the surface of the conveyor, the suction caps applying a suction attachment to the boards when they come into contact therewith.
Typically lengths of cornice are added to the pack, eg at the stacking means, to complete the customer order.
The stacking means may be associated with a transfer conveyor for conveying the stack of boards away from the stacking means.
Further advantageously the stacking means may be associated with a means for attaching a pack of boards to each other to form a single article suitable for transport, eg in the form of a strapping applicator.
The stacking means may also be associated with a means for applying a cover sheet to a pack and also enclosing the pack in shrink wrap.